This study will determine if in individuals with radiographic abnormalties consistent with their asbestos exposure, there are increased numbers of activated alveolar macrophages which release increased quantities of peptide growth factors that signal mesenchymal cells to proliferate. The investigators will measure macrophage growth factors at the mRNA level to evaluate gene expression and macrophage supernatants to quantitate spontaneous protein release. The lab was used for the following: BAL analysis, RNA Isolation, ultracentrifugation, recombinant DNA techniques, blood separation, ELISA and use of laminar flow hoods.